Optical storage systems have become a commonplace technology in modern computing systems. Nearly all computing systems now come equipped with the ability to read and write data on CD's while newer systems are being fitted with DVD read/write systems. Interestingly, the form factor for CD media and DVD media are substantially identical. The ability to put more data in the same space has come about with the use of shorter wavelengths for reading and writing, smaller track pitch, and multiple layers. Indeed, where CD technologies may currently provide approximately 700 MB of storage/CD, DVD technologies may currently provide approximately 8.5 GB of storage. While these storage systems have provided users with the ability to easily store large quantities of data, they are not without their limitations.
For example, writing to blank write once optical discs, such as CD-R, DVD-R, WORM, and the like, occasionally fails due to shocks or bumps delivered to the system during write operations. When a shock event of sufficient magnitude occurs, an optical drive may write off-track or lose focus rendering an optical disc unreadable in which cases the drive informs the system of a burn failure. Such shock events result in loss of media as well as time spent in writing data to the media up to the point of burn failure. In contrast, read errors do not generally render a disc unreadable because the data is typically not corrupted. Rather, read errors generally require nothing more than realigning a read seeking the optical head to continue backward and re-reading the data.
In addition, because of wide proliferation in portable computing systems, optical write systems are much more likely to experience shock events due to the nature and use of portable computing systems. Indeed, some portable computing systems may be configured with inertial damping devices provided to lower the rate of shock event related failures. Finally, as optical storage systems continue to evolve, shorter wavelengths, smaller track pitch, and multiple layers may be utilized to provide increased data density which may, in turn, contribute to increased write failure rates by effectively making systems more sensitive to shock events due to decreased tolerances.
What is needed is a system that provides improved protection from shock events in modern computing systems that is transparent to a user. Therefore, systems and methods of shock recovery in writable optical disk systems are presented herein.